Tubular organs in the body may have a convoluted cavity configuration. The gastrointestinal tract, for example, starts from the oral cavity and proceeds through the esophagus, stomach, duodenum and small intestine, which is a long tube that folds many times to fit inside the abdomen. The small intestine is connected to the large intestine, which begins with the cecum, a small saclike evagination, then continues with the ascending colon, transverse colon, descending colon and the sigmoid (S-shaped) colon to the rectum. These body lumens may suffer from pathologies, which can affect the anatomy or configuration of the lumen. For example, strictures, narrowing or closure of a normally configured lumen can be caused by calcification or by the presence of scat tissue or a tumor. Structures of the esophagus are a common complication of chronic gastroeosophagaeal reflux disease (GERD). Acute, complete obstruction of the esophagus may occur when food is lodged in the esophageal stricture. Endoscopy is usually employed to retrieve the food and relieve the obstruction.
Several procedures are available for stretching (dilating) the strictures without having to resort to surgery. These involve placing a balloon or a dilator across the sticture during an endoscopy procedure.
Methods for diagnosis of body lumens are usually symptom related or invasive Non-invasive techniques of diagnosing the gastrointestinal (GI) tract include utilizing solid non-degradable swallowable autonomous electronic or magnetically marked capsules. These autonomous capsules include capsules for measuring motility in the GI tract, gastric pH (such as the Heidelberg capsule) and in vivo temperature (such as the CoreTemp™ capsule). Also, gastric transit may be measured by using biomagnetic measuring equipment such as a magnetically marked capsule, which is a solid non-degradable oral dosage form containing powdered magnetite encapsulated in silicone rubber (W. Weitschies, R. Kotitz, D. Cordin, L. Trahms, (1997), J Pharm Sci, 86:1218-1222). Such capsules are typically propelled through the GI system by peristalsis. These non-invasive methods enable reaching parts of the intestine, especially distal parts of the small intestine (jejunum and ileum) that cannot be reached by other methods. However, in rare cases of severe strictures in the GI tract, swallowing of a solid bolus (such as an electronic or magnetically marked capsule) may cause obstruction of the GI tract.
Also, drug delivery devices that are solid non-degradable boluses may often be swallowed. Drug delivery devices may include diffusion controlled systems or environmentally responsive systems. In these systems there may be a combination of polymer matrices and bio active agents (typically drugs) that allow for a drug to diffuse through the pores or macromolecular structure of the polymer upon introduction of the system in vivo. In some cases the devices are swelling-controlled release systems that are based on hydrogels. Hydrogels are polymers that will swell without dissolving when placed in water or other biological fluids. Thus, the swelling-controlled systems are initially dry and, when placed in the body, will absorb fluids and swell. The swelling increases the polymer mesh size enabling the drug to diffuse through the swollen network into the external environment. These systems are typically essentially stable in an in vivo environment and do not change their size either through swelling or degradation. The swallowing of these systems may thus, in cases of strictures in the GI tract, cause obstruction of the GI tract.
Non-invasive methods for detection of strictures, specifically in the GI tract, usually include x-ray series that are based on intake of x-ray opaque (radio-opaque) material (barium, gastrographine, or others). The material resides for some time on the walls of the GI tract, enabling examination of the x-ray images of the GI tract. This technique has several drawbacks, namely, low detection rate and exposure to x-ray radiation.
In-vivo devices, pills, or other medical systems may need to pass through the GI tract. However, it may be difficult to predict if such devices, pills, or systems may achieve safe passage through the GI tract, short of actually attempting to pass the objects through the tract.
Therefore, there exists a need for an efficient and low-hazard method of examining a body lumen. Specifically, there exists a need for a safe and high performing method of detecting abnormalities in a body lumen, such as abnormal motility in the GI tract, strictures or other configurational abnormalities in body lumens. In addition, there exists a need to determine whether objects of a certain size and/or shape may pass safely through the GI tract.